U.S. Pat. No. 5,681,231, which is incorporated herein by reference in its entirety, discloses a collapsible structure, in particular a game goal, with an elbow joint having an arm with a gap therein. A frame member inserts into the gap in a fixed or upright position and is removed from the gap to collapse the structure. A flexible member connected to the frame member and the portion of the elbow having the gap allows the frame member to move into and out of the joint while remaining connected to the overall structure.
U.S. Pat. No. 6,220,776, which is incorporated herein by reference in its entirety, discloses a corner or straight joint for a collapsible structure with a socket portion that accommodates a movable member with multiple degrees of motion. In this joint the movable member is connected with a threaded or otherwise twistable connection to the rod of a heim joint which rotates on a roll pin. The movable portion moves in and out of the socket portion to erect and collapse the structure, as frame members are attached to the fixed and movable portions of the joint.
U.S. Pat. No. 7,377,714, which is incorporated herein by reference in its entirety, discloses a mechanical joint formed from a hollow structure of material shaped to form a socket. The socket is configured to snap fit with a movable member. A flexible member is positioned in the socket and is attached to the movable member, and the flexible member can twist to permit the movable member to permit the movable member to be located in a variety of positions.
U.S. Patent Publication No. 2010/00184538, which is incorporated herein by reference in its entirety, discloses a game goal that collapses both vertically and laterally. The goal includes joints and brackets that facilitate the collapse of the goal such that during vertical collapse, the forward uprights of the goal fold below the goal's lower rear support member to enhance the ability to transport the goal.